The group is also asking supporters to sign an online petition calling on Twitter to "uphold human-rights based standards of conduct, particularly when it comes to freedom of expression."

The 7-year-old San Francisco-based social media giant has 255 million monthly active users around the world, its website reports. Twitter says 500 million messages of 140-characters or less, known as "tweets," are sent daily.

Some of those messages, however, are not well received in some corners of the globe. Since May 14, Abdul Batin of the Pakistan Telecommunication Authority in Karachi has filed five requests with Twitter to block certain sites that violate the "Pakistan Penal Code," most notably Pakistan's blasphemy laws, according to chillingeffects.org, an anti-censorship website.

It's an open question as to whether or not the Pakistan Telecommunication Authority has the authority to make determinations of blasphemy and to request the Twitter takedown. Bolo Bhi, an advocacy group whose name in the Urdu language of Pakistan means "Speak Up," notes the law creating the telecom authority "does not in any form give PTA the authority to arbitrarily restrict content on the Internet."

"The blocking of these tweets in Pakistan — in line with the country-specific censorship policy Twitter unveiled in 2012 — is the first time the social network has agreed to withhold content there," The New York Times reported after the blockages were discovered. "A number of the accounts seemed to have been blocked in anticipation of the fourth annual 'Everybody Draw Muhammad Day' on May 20."

Twitter, through a spokesman, said it would not comment. Others have pointed out that Twitter users in Pakistan need only adjust their "country setting" in the Twitter mobile app to see the supposedly blocked content.

EMNA blasted Twitter for departing from its previous "pro-human rights stance" and giving into Pakistan's requests. "There was a time when Twitter was rightly lauded for the role it played during the Arab Spring, facilitating communication between those resisting oppressive governments," the group stated. "In fact, Egypt’s dictators tried to disable Twitter, and then internet access completely, before being overwhelmed by the protests that began at Tahrir Square. Governments in Tunisia and Iran tried similar tactics to suppress protests against those oppressive regimes."

And according to the Electronic Frontier Foundation, Twitter's retreat from the digital liberty front lines is disappointing: "Supporters of Twitter's position may point out that Twitter is still the least-bad actor in this space. Facebook regularly complies with government demands for censorship, as does Google. But being the least-bad actor is not good enough. By setting a high standard in defense of free expression, Twitter was once the leader in a race to the top. There's no pride in sinking to the bottom along with everyone else."

Twitter is not the only social media network facing censorship demands from Pakistan. On Friday, June 6, Facebook reversed its agreement to a PTA request to block its page for "Laal," or "Red," an alternative rock band in the country, according to the Delhi Daily News: "The band added that it would continue its fight against the ban on other progressive pages that are suffering from censorship imposed by the government. The group announced that it will celebrate the victory," the newspaper reported.